Grommet

ABSTRACT

To achieve high waterproofness, a grommet that is attached so as to cover a shield pipe and a corrugated tube so as to bridge therebetween includes a pipe-side end portion that is formed in a tubular shape capable of being sealingly connected to an outer circumferential side of the pipe, and a corrugated-side end portion that is formed in a tubular shape capable of being sealingly connected to an outer circumferential side of the corrugated tube. A plurality of sealing lips that closely contact to an outer surface of the shield pipe are formed on an inner surface of the pipe-side end portion. The sealing lips are disposed inside and outside a width region W that is fastened by a fastening band disposed on an outer surface of the pipe-side end portion.

This is a Division of application Ser. No. 14/324,661 filed Jul. 7,2014, which claims the benefit of Japanese Patent Application No.2013-140911 filed Jul. 4, 2013. The disclosure of the prior applicationsis hereby incorporated by reference herein in its entirety.

TECHNICAL FIELD

The present disclosure relates to a grommet.

BACKGROUND

Conventionally, for hybrid cars and electric cars, wiring is oftenarranged by inserting a wire harness routed, for example, between thebattery and the inverter, or between the inverter and the motor, into ametal pipe. The metal pipe is disposed under the floor of the automobilebody along the front-back direction. This metal pipe has the function toshield the wire and the function to protect it from air-borne stones andthe like. After being guided into the engine compartment, the metal pipemay be connected to the inverter side via a metal braid portion. Themetal braid portion, which is formed by braiding metal strands into amesh form, is attached to cover an end portion of the metal pipe, and isconnected to the end portion by being crimped with a crimp ring.Additionally, a waterproof grommet made of a rubber material may befitted to the connection portion between the metal pipe and the metalbraid portion, as depicted, for example, in FIG. 1 of JP 2006-311699A.

SUMMARY

Meanwhile, it is conceivable that high pressure wash water is alsosplashed to a place where a grommet may be attached. However, theabove-described conventional structure cannot sufficiently cope withsuch a situation, and there is the concern that the sealing between thecorrugated tube and the grommet, and between the pipe and the grommetmay be reduced over time.

The embodiments described herein have been completed in view of theabove-described situation, and it is an object of the embodiments toprovide a grommet that can achieve enhanced waterproofness.

A grommet according to one embodiment is a grommet that is attached tocover, for example, a pipe, inside which a wire is inserted, and, forexample, a corrugated tube, so as to form a bridge therebetween, thecorrugated tube being formed in a flexible bellows by alternatelyrepeating ridges and troughs, and in which the wire drawn from an endportion of the pipe may be accommodated, including: a pipe-side endportion that may be formed in a tubular shape capable of being sealinglyconnected to an outer circumferential side of the pipe; acorrugated-side end portion that may be formed in a tubular shapecapable of being sealingly connected to an outer circumferential side ofthe corrugated tube; and a plurality of sealing lips that may beprovided on inner surfaces of the corrugated-side end portion and thepipe-side end portion so as to contact, for example, closely contact, toan outer surface of the pipe or the troughs of the corrugated tube, atleast those of the sealing lips that are disposed at the pipe-side endportion being disposed inside and outside a width region that isfastened by a fastening band disposed on an outer surface of thepipe-side end portion.

The sealing lips located inside the width region of the fastening bandare susceptible to degradation due to the influence of the fasteningforce of the fastening band, and tend to undergo a reduction in thesealing function over time.

Nevertheless, the embodiments described herein are also effective inmaintaining the sealing function over time because sealing lips are alsodisposed outside the width region of the fastening band, and thereby,these lips can function as auxiliary lips.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view showing an area around a portionwhere a grommet is attached;

FIG. 2A is a cross-sectional view of the grommet;

FIG. 2B is a zoomed-in view of a portion of the grommet in FIG. 2A;

FIG. 2C is a zoomed-in view of a portion of the grommet in FIG. 2A;

FIG. 3 is a cross-sectional view at the portion where the grommet isattached;

FIG. 4A is a cross-sectional view showing a modification of the grommet;

FIG. 4B is a zoomed-in view of a portion of the grommet in FIG. 4A; and

FIG. 4C is a zoomed-in view of a portion of the grommet in FIG. 4A.

EMBODIMENTS

A preferred embodiment will now be described.

In the grommet according to the preferred embodiment, a tapered surfacemay be formed at a leading end portion of the outer surface of at leastthe pipe-side end portion of the pipe-side end portion and thecorrugated-side end portion.

The grommet may be attached in a state in which it spans opposite endson the pipe side and the corrugated tube side. In this case, assuming,for example, that high pressure wash water is dashed to the end face ofat least the pipe-side end portion of the pipe-side end portion and thecorrugated-side end portion, the end face is likely to receive thepressure of the high pressure wash water if it is formed so as to risesteeply. Accordingly, there is the possibility that the end face portionmay be lifted, causing the wash water to enter inside the grommet. Inthis respect, with the above-described configuration, the high pressurewash water can be released along the taper of the tapered surface.Therefore, the lifting of the end face portion can be effectivelyreduced, thus maintaining the sealing function of the grommet.

Preferably, a portion that is located on the inner surface of thecorrugated-side end portion and that is included within the width regionfastened by the fastening band may be provided with: the sealing lips;and a restraining receiving portion against which a protruding end faceof the ridges of the corrugated tube abuts so as to restrain collapsingof the sealing lips.

With this configuration, even if the fastening band excessively fastensthe corrugated-side end portion of the grommet, the fastening force isreceived by the protruding end face of the ridge of the corrugated tube,and therefore, the sealing lips will not be excessively collapsed.Accordingly, it is possible to maintain the sealing function of thesealing lips.

Embodiment 1

Next, Embodiment 1 of the grommet will be described with reference tothe drawings. In the present embodiment, a description will be given ofa grommet G1 that is provided in the routing path of a wire harness WHthat connects a battery mounted in, for example, a vehicle compartmenton, for example, the rear side to an inverter mounted in an enginecompartment in, for example, a hybrid car.

As shown in FIG. 1, the wire harness WH may be made up of a plurality ofwires. A part of the wire harness WH is inserted into a shield pipe 1that may be made of a conductive metal. For example, the shield pipe 1may be made of aluminum or an aluminum alloy, and may be disposed underthe floor of the vehicle body. Additionally, as shown in FIG. 3, theleading end of the shield pipe 1 may be flared in, for example, atrumpet shape to form a flared portion 2.

One end of a metal braid portion 3 may be connected to one end portionof the shield pipe 1. The metal braid portion 3 may be formed bybraiding, for example, copper-based metal strands having, for example,tin-plated surfaces into, for example, a mesh-like, long tubular shape.The wires that have been drawn from the shield pipe 1 may be inserted inthe metal braid portion 3. The metal braid portion 3 may be attached tocover the outer surface of the shield pipe 1, and may be crimped, forexample, fixedly crimped, using, for example, crimp ring 4.

The crimp ring 4 may be a known crimp ring. In its natural state, a partof a ring-shaped main portion 4A of the crimp ring 4 is widened radiallyoutward and protrudes as a crimp portion 4B. At the time of fasteningthe crimp ring 4, the main portion 4A can be shifted to a reduceddiameter state by, for example, pinching the basal portions of the crimpportion 4B to move close to each other, and thereby, the metal braidportion 3 may be, for example, fixedly crimped to the shield pipe 1.

The metal braid portion 3 may be inserted in the corrugated tube 5except for a part of its area on the side connected to the shield pipe1, and an end portion of the metal braid portion 3 that may extend allthe way to the connection to an inverter (not shown). Thus, theshielding properties of the wire harness WH are ensured over the lengthfor which the shield pipe 1 and the metal braid portion 3 are provided.

The corrugated tube 5 may be formed of, for example, a synthetic resinmaterial and may be in a unitary and elongated tube shape. Thecircumferential surface of the corrugated tube 5 may be formed in abellows shape in which ridges 5A and troughs 5B may be repeated, and hasgood flexibility. The grommet G1 that accommodates the metal braidportion 3 exposed from the corrugated tube 5 is attached between thecorrugated tube 5 and the shield pipe 1, bridging the corrugated tube 5and the shield pipe 1.

The grommet G1 may be formed of, for example, a rubber material, forexample, a ethylene propylene diene monomer rubber (EPDM) as, forexample, a unitary body. The axial central portion of the grommet G1 mayserve as a base portion 6, and an accommodating portion 7 that bulgesradially outward and over a predetermined length range in thecircumferential direction may be formed on a part of the base portion 6.The crimp portion 4B of the crimp ring 4 may be accommodated in theinterior space of the accommodating portion 7.

A pipe-side end portion 8 may be formed on one end side of the grommetG1, and a corrugated-side end portion 9 may be formed on the other endside thereof. Both the pipe-side end portion 8 and the corrugated-sideend portion 9 may be formed, for example, in a cylindrical shape. Thepipe-side end portion 8 allows an end portion of the shield pipe 1 to beinserted inside and the corrugated-side end portion 9 can be fitted onthe outer circumferential side of the corrugated tube 5.

Two ring-shaped protrusions 10 may be formed at an interval around theentire circumference of the outer surface of the pipe-side end portion 8at positions that may be near the end portion. The portion between thetwo protrusions 10 may serve as an attachment groove 11 for positioninga fastening band 12. The the width of the attachment groove 11 may beset to be slightly wider than the width of the fastening band 12.

Since the fastening band 12 may be a known fastening band, a generaldescription of a fastening band is provided. The fastening band 12 maybe formed of a synthetic resin material, and may preferably in a unitaryand band-shaped body. At one end portion of the fastening band 12, alock portion 13 may be formed that allows the other end side of thefastening band 12 to be inserted therethrough. On the other end side, anumber of locking edges that may be serrated (not shown) may be formedalong the length direction. Additionally, flexible locking pawls (notshown) may be formed inside the lock portion 13. Pulling the other endside that is passed through the lock portion 13 causes the locking pawlsto be selectively locked to the locking edges. This allows for thepipe-side end portion 8 to be tied and, for example, fixedly fastened tothe shield pipe 1.

On the other hand, as shown in FIGS. 2A-2C, a plurality of pipe-sidesealing lips 14-1 to 14-4 may be provided on the inner surface of thepipe-side end portion 8. The pipe-side sealing lips 14-1 to 14-4 may beformed integrally and protrudingly around the entire circumference, andeach of them may contact, for example, closely contact, the outersurface of the shield pipe 1 to provide sealing. In the presentembodiment, the pipe-side sealing lips 14-1 to 14-4 may comprise one(first lip 14-1) provided at the opening edge of the pipe-side endportion 8, one (second lip 14-2) provided at a portion below, forexample, directly below, the axial central portion of the attachmentgroove 11, one (third lip 14-3) provided at a portion displaced, forexample, slightly inward from a portion below, for example, directlybelow the protrusion 10 located away from the opening edge, and one(fourth lip 14-4) provided at a portion displaced further inward fromthe third lip 14-3. Thus, for example, in the present embodiment, onlythe second lip 14-2 may be located in a width region (the region withinthe range indicated by W in FIG. 3) that is fastened with the fasteningband 12, and the other lips may be disposed so as to be displaced fromthat width region and may function as auxiliary lips. Furthermore, theprotruding heights of the pipe-side sealing lips 14-1 to 14-4 may bemade uniform.

Additionally, a pipe-side tapered surface 15 may be formed at theleading end of the outer surface of the pipe-side end portion 8. Thatis, an annular rising surface 18 that rises at a substantially rightangle to the axis may be formed on the end face of the pipe-side endportion 8. Also, the above-described pipe-side tapered surface 15 may beformed around the entire circumference, from the outer circumferentialedge of the rising surface 18 to the top portion of the protrusion 10located on the leading end side.

On the other hand, a mount groove 16 for positioning the fastening band12 may be recessed around the circumference, for example, the entirecircumference of the axial central portion on the outer surface of thecorrugated-side end portion 9. A corrugated-side tapered surface 17 mayalso be formed at the leading end of the outer surface of thecorrugated-side end portion 9. That is, an annular rising surface 19that rises at a substantially right angle to the axis may be formed onthe end face of the corrugated-side end portion 9. Also, theabove-described corrugated-side tapered surface 17 may be formed aroundthe circumference, for example, the entire circumference at apredetermined locking angle from the outer circumferential edge of therising surface 19. In the present embodiment, the inclination angle α1of the pipe-side tapered surface 15 may be set to be smaller than theinclination angle α2 of the corrugated-side tapered surface 17 (α1<α2).

As shown in FIGS. 2A-2C, a plurality of corrugated-side sealing lips20-1 to 20-4 may be provided on the inner surface of the corrugated-sideend portion 9. The corrugated-side sealing lips 20-1 to 20-4 may beprovided at a uniform pitch in order from the one provided at theopening edge of the corrugated-side end portion 9 to the inner side.This pitch may be the same as the pitch of the ridges 5A and the troughs5B of the corrugated tube 5. The protruding height of thecorrugated-side sealing lips 20-1 to 20-4 may be set to be higher thanthat of the pipe-side sealing lips 14-1 to 14-4. In a state in which theend portion of the corrugated tube 5 may be inserted in thecorrugated-side end portion 9, the protruding end portions of thecorrugated-side sealing lips contact, for example, closely contact tothe bottom faces of the troughs 5B of the corrugated tube 5 to providesealing.

Of the corrugated-side sealing lips 20-1 to 20-4, the two sealing lips(20-2, 20-3) located at the center may be positioned such that they maybe at least partly included within the width region of the fasteningband 12 that securely fastens the corrugated-side end portion 9 withinthe mount groove 16, whereas the corrugated-side sealing lip 20-1provided at the opening edge and the corrugated-side sealing lip 20-4provided at the innermost portion may be both positioned outside thewidth region W, and may function as auxiliary lips.

Furthermore, one of the ridges 5A of the corrugated tube 5 may bepositioned within the width region W of the fastening band 12 at thecorrugated-side end portion 9. In FIG. 3, the ridge 5A may be positionedsubstantially directly below the fastening band 12, and the ridge 5A mayabut against the portion of the inner surface of the corrugated-side endportion 9 that may be located between the two corrugated-side sealinglips 20-2 and 20-3 positioned within the width region W. Thus, thisportion can function as a restraining receiving portion 21 that avoidsan excessive collapsing of the corrugated-side sealing lips 20-1 to 20-4included within the width region W in the case where the fastening band12 may be excessively fastened.

In the present embodiment 1, the grommet G1 may be mounted, for example,in the following manner. First, a part of the metal braid portion 3inserted in the corrugated tube 5 may be pulled outside, and may beattached to cover the outer surface of an end portion of the shield pipe1. Then, the crimp ring 4 that has been previously fitted to the shieldpipe 1 side may be moved to the covered portion. By crimping the crimpportion 4B of the crimp ring 4 in this state, the metal braid portion 3may be crimped, for example, fixedly crimped to the shield pipe 1.

Thereafter, the grommet G1 that has been previously fitted to the shieldpipe 1 side or the corrugated tube 5 side may be moved toward thecrimped area of the metal braid portion 3. Then, while the crimp portion4B of the crimp ring 4 is being accommodated in the accommodatingportion 7 of the grommet G1, the corrugated-side end portion 9 may beattached to cover the outer circumferential side of the end portion ofthe corrugated tube 5 and the pipe-side end portion 8 may be attached tocover the outer circumferential side of the shield pipe 1. Thereby, thegrommet G1 may be attached so as to span the shield pipe 1 and thecorrugated tube 5.

At this time, the pipe-side sealing lips 14-1 to 14-4 may contact, forexample, closely contact, the outer surface of the shield pipe 1 at thepipe-side end portion 8, and the corrugated-side sealing lips 20-1 to20-4 may enter the corresponding troughs 5B of the corrugated tube 5 andcontact, for example, closely contact, the respective bottom faces atthe corrugated-side end portion 9.

Finally, the fastening band 12 may be fastened within the attachmentgroove 11 of the pipe-side end portion 8, and the fastening band 12 maybe fastened in the mount groove 16 at the corrugated-side end portion 9.Thereby, the mounting of the grommet G1 may be completed.

With the grommet G1 mounted in the above-described manner, it ispossible to prevent water from entering between the grommet G1 and theshield pipe 1 or between the grommet G1 and the corrugated tube 5 byusing, for example, the pipe-side sealing lips 14-1 to 14-4 and, forexample, the corrugated-side sealing lips 20-1 to 20-4.

At the pipe-side end portion 8 and the corrugated-side end portion 9,the pipe-side sealing lip 14-2 and the corrugated-side sealing lips 20-2and 20-3 may be included within the width regions W of the fasteningbands 12 or may be positioned below, for example, directly below.Accordingly, an appropriate sealing pressure can be applied to thepipe-side sealing lip 14-2 and the corrugated-side sealing lips 20-2 and20-3 as long as the fastening bands 12 are appropriately fastened. Evenif the fastening band 12 is excessively fastened on the corrugated tube5 side, the ridge 5A of the corrugated tube 5 may be positioned below,for example, directly below, the fastening band 12 so as to abut againstthe restraining receiving portion 21. Thus, the corrugated-side sealinglips 20-2 and 20-3 will not be collapsed excessively, and the sealingproperties are achieved.

Since compressive pressure constantly acts from the fastening bands 12on the pipe-side sealing lip 14-2 and the corrugated-side sealing lips20-2 and 20-3 that may be included within the width regions of thefastening bands 12, it is conceivable that these sealing lips maydeteriorate over time, resulting in a reduction in the sealing function.However, in the present embodiment, the pipe-side sealing lips 14-1,14-3, and 14-4 and the corrugated-side sealing lips 20-1 and 20-4 may bealso positioned outside the width regions W of the correspondingfastening bands 12 so as to sandwich the width regions W. The lips thatmay be located outside the width regions W slowly undergo deteriorationover time, and may be effective in maintaining the sealing propertiesfor a long time. It is preferable that this structure is provided at thepipe-side end portion 8 to which high pressure wash water may besplashed.

Furthermore, when considering sealing properties, it is possible thathigh pressure wash water may be splashed to the end face of thepipe-side end portion 8. It is also possible that the wash water issplashed to the end face of the corrugated-side end portion 9.Conventionally, this end face may have a large area of the risingsurface that rises at a right angle to the axis, and therefore, there isthe possibility that the end face may be lifted, allowing entry ofwater. However, in the present embodiment, the provision of thecorrugated-side tapered surface 17 in addition to the pipe-side taperedsurface 15 makes the areas of the rising surfaces 18 and 19 sufficientlysmaller than those of the conventional configuration. In addition, thepressure of high pressure wash water may be released along the twotapered surfaces 15 and 17, and it is therefore possible to reliablyreduce situations where the end faces of the two end portions 8 and 9 ofthe grommet G1 may be lifted, and maintain the sealing properties.

Furthermore, since the corrugated-side sealing lips 20-1 to 20-4 thatmay be formed at the opening edge enter the troughs 5B of the corrugatedtube 5 at the corrugated-side end portion 9, this also suppresses theoccurrence of the lifting. In view of this, in the present embodiment,the lifting does not easily occur even if the inclination angle α2 ofthe corrugated-side tapered surface 17 is set to be larger than theinclination angle al of the pipe-side tapered surface 15.

Accordingly, the thickness of the corrugated-side end portion 9 can beincreased more than that of the pipe-side end portion 8. The corrugatedtube 5 side may be the side on which the wire routing direction can beappropriately changed. Accordingly, it may be useful for the purpose ofensuring the followability to the corrugated tube 5 that a certainamount of thickness is ensured for the corrugated-side end portion 9 atthe time of changing the routing direction so as to be able to increaserigidity.

Conventionally, the corrugated-side end portion 9 may be connected tothe corrugated tube 5 by tape winding without using the fastening band12. However, it has been pointed out that such tape winding has lowerconnection reliability due to operational variations. Fastening usingthe fastening band 12 as in the present embodiment can relatively easilyprovide a constant fastening force by using, for example, a jig or thelike. Thus, a higher connection reliability may be achieved.Furthermore, although tape winding may cause the problem of tapedeterioration over time, the present embodiment may not have such aproblem.

FIGS. 4A-4C shows a modification of the corrugated-side sealing lips20-1 to 20-4 and the pipe-side sealing lips 14-1 to 14-4. In a grommetG2 as shown in FIGS. 4A-4C, of the corrugated-side sealing lips 20-1 to20-4 and the pipe-side sealing lips 14-1 to 14-4, the pipe-side sealinglip 14-1 and the corrugated-side sealing lip 20-1 that may be located atthe opening edges may be set to have a higher protruding height thanothers. The reason for this is to cope with the possibility that theentire opening edges of the pipe-side end portion 8 and thecorrugated-side end portion 9 may be flared when the fastening bands 12are fastened, and the sealing functions of the corrugated-side sealinglip 20-1 and the pipe-side sealing lip 14-1 located at the opening edgesmay be reduced.

This can also contribute to an improvement in the sealing properties ofthe grommet G2.

The present disclosure is not limited to the embodiments describedabove, and shown in the drawings. For example, the following embodimentsalso fall within the technical scope of the present disclosure.

Although the metal braid portion 3 and the corrugated tube 5 may beformed separately in the above-described embodiment, the metal braidportion 3 may be, for example, inserted in the corrugated tube 5 andformed integrally therewith.

Although the shield pipe 1 may be formed only of a metal material in theabove-described embodiment, the shield pipe 1 may be formed, forexample, by inserting a metal tubular body in a resin pipe.

The shield pipe 1 and the metal braid portion 3 may be provided alongthe routing region of the wire harness WH to ensure the shieldingfunction in the above-described embodiment. However, in the case ofusing the present embodiment under conditions that do not requireshielding, the pipe may not be a conductive metal and the metal braidportion 3 may be omitted.

What is claimed is:
 1. A grommet, wherein the grommet is capable ofbeing attached to cover at least a portion of a pipe; the grommetcomprising: a pipe-side end portion that is formed in a tubular shapeand is capable of being sealingly connected to an outer circumferentialside of the pipe; and a plurality of sealing lips are formed inside of aleading end of the grommet, wherein a tapered surface is formed at theleading end portion of an outer surface of the pipe-side end portion,the sealing lips are capable of being fastened by a fastening banddisposed on the outer surface of the pipe-side end portion, and a widthregion fastened by the fastening band is located on a rear side of thegrommet away from the tapered surface.
 2. The grommet according to claim1, wherein an annular rising surface that rises at a substantially rightangle to a length-wise axis of the grommet is formed on an end face ofthe pipe-side end portion, and the tapered surface connects to theannular rising surface.
 3. The grommet according to claim 1, wherein thesealing lips are disposed inside and outside the width region fastenedby the fastening band.
 4. The grommet according to claim 1, wherein thesealing lips are formed at the front and rear sides of the width regionfastened by the fastening band.
 5. The grommet according to claim 1,further comprising protrusions for positioning the band.
 6. The grommetaccording to claim 5, wherein the tapered surface forms one protrusionfor positioning the band.